Question: If $x \bigtriangleup y = 7y+2$ and $x \oplus y = 3x-y$, find $2 \oplus (1 \bigtriangleup -2)$.
Explanation: First, find $1 \bigtriangleup -2$ $ 1 \bigtriangleup -2 = (7)(-2)+2$ $ \hphantom{1 \bigtriangleup -2} = -12$ Now, find $2 \oplus -12$ $ 2 \oplus -12 = (3)(2)-(-12)$ $ \hphantom{2 \oplus -12} = 18$.